This application claims the benefit of U.S. Provisional Application Nos. 60/017,073, filed on Apr. 30, 1996 and 60/027,270, filed on Sep. 27, 1996.
This invention relates to seals and sealing arrangements and especially to seals and sealing arrangements for near atmosphereic, closed production chambers.
In the process of manufacturing Tyvek(copyright) spun bonded olefin, a spin solution is carried from a solutioning system to a plurality of spinpacks in a spin cell. Unfortunately, it is quite common that a spinpack becomes fouled during the manufacturing process and needs to be shut down and replaced. Although the manufacturing process has been engineered such that production can continue while a single spinpack is not operating, the spinpack is positioned within a spin cell that is closed to prevent or minimize the release of the spin agent.
Presently, the spin solution is a combination of olefin polymer and a CFC spin agent and access to the spinpack is provided from above the spin cell with a number of precautions and procedures to minimize the release of vaporized CFC spin agent which is substantially heavier than air. However, E. I. du Pont de Nemours and Company (DuPont) has developed a new process for manufacturing Tyvek(copyright) spun bonded olefin in light of the need to stop using the CFC spin agent because of the belief that such CFC""s are ozone depleters. In the new process, pentane will be used as the spin agent and thus many changes to the process are necessary in light of the flammability of pentane that did not exist with the CFC spin agent. One consideration is that access by human personnel to the spin cell for changing spinpacks will be more limited.
Accordingly, it is an object of the present invention to provide an arrangement and process for changing spinpacks in a spin cell which may be accomplished with minimal exposure of personnel to the spin cell environment.
It is a further object of the present invention to provide a remotely operated coupling system for disconnecting a spinpack and connecting a new spinpack into a spin position.
It should be noted that there are prior art systems for making connections of pipes remotely. However, such prior art systems are designed to include configured surfaces which must be generally axially aligned prior to bringing one pipe into contact with the second pipe. Thus, the one pipe is first moved into a position where its axis is generally co-extensive with the axis of the second pipe and then the first pipe is conveyed axially toward the second pipe. Such an arrangement may be termed an axial entry coupling system. There are instances when remote operation is desirable but axial entry is not practical. For example, in the situation where the spinpacks are being switched in and out, each spinpack has to fit down through a portal or hatch into the spin cell in a manner which seals with the spin cell while making numerous other fluid and electrical connections. The sealing arrangement restricts the freedom of movement of the spinpack, particularly as the spinpack approaches its operational position, at the base of the portal. It would require a complicated arrangement to make an axial entry connection to a pipe oriented laterally to the portal.
As mentioned above, there are remotely operated connectors which require the two step approach of axial alignment and then axial entry that is unsuitable for certain applications. Specifically, a remotely operated connector offered in the Grayloc(copyright) product catalog by Gray Tool Company (a subsidiary of Combustion Engineering) shows a system for connecting two pipe ends with specially designed mating surfaces. The system has a clamping mechanism with two pivoting clamps each having an arcuate, wedge shaped surface that pivots toward one another to engage a corresponding surface on the pipe flange. With this design, the two pipe flanges must first be aligned so that the two pipes are generally coaxial. Then the pipes are brought together axially so that the wedge surfaces on the pipe flange may pass between the pivoting clamps and engage a conical seal. This arrangement would not accommodate a lateral entry of the pipe.
The term xe2x80x9clateral entryxe2x80x9d or xe2x80x9clateral approachxe2x80x9d are each intended to mean an arrangement where the end of one pipe is brought to the end of another pipe for the purposes of making a connection between the two pipes such that the approach of the one pipe is from a direction which is lateral with respect to the axes of the two pipes. In the perfect sense of xe2x80x9clateral entryxe2x80x9d, the two pipes have parallel axes and the direction of approach is perpendicular to the axes of each of the pipes. It should be noted that the pertinent portion of the pipes at which to consider the axis of each pipe is at the end that is to be connected to the other pipe. It should also be recognized that one pipe need not be fixed or stationary, but that both pipes may be in motion toward a position for connection and such direction of motion need not be primarily in the lateral direction. It is the relative motion of the pipes to one another that provides for lateral approach.
Accordingly, it is a further object of the present invention to provide a pipe coupling arrangement that provides for lateral entry of one pipe to the other.
It is a further object of the present invention to provide an improved arrangement for seal a closed industrial environment such as a closed chamber or cell which includes portions or equipment that are dhanged or replaced during operation.
The above and other objects of the invention are accomplished by the provision of a process which includes providing the equipment into the chamber through a portal wherein the portal and equipment includes a sealing system which includes a skirt and a circumscribing channel arranged entirely around the portal with a liquid therein and wherein the skirt projects into the liquid in the channel so that the cover and skirt close and seal the portal and the chamber. The portal is closed with a gate from within the chamber isolating the equipment from the interior of the chamber and the equipment is removed from the portal such that the skirt comes out of the channel. The replacement equipment is installed into the portal such that the replacement equipment forms a similar seal as the replaced equipment and the gate is opened within the chamber to the portal so that the equipment is open to the interior of the chamber.
The objects of the invention are also accomplished with a sealing system including a channel formed of a generally vertically upright inner wall arranged to approximately circumscribe the opening in the chamber, a generally concentric outer wall spaced from the periphery of said inner wall and a closed bottom between said inner and outer wall. A liquid sealing agent fills a substantial portion of the channel and a skirt is arranged to fit into the channel to close the space around the opening in the chamber. The channel is attached either the chamber or the equipment and the skirt is attached to the other such that as the equipment is brought into the opening, the skirt and the channel form a seal to close the opening around the equipment.